class Middleman::ConfigExtension

def initialize(app, config={}, &block)
  @descriptors = {}
  @ready = false
  self.class.exposed_to_config.each do |k, v|
    @descriptors[k] = []
    define_singleton_method(:"__original_#{v}", &method(v))
    define_singleton_method(v) do |*args, &b|
      proxy_method_call(k, v, args, &b)
    end
  end
  super
end